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Subject[PATCH 5.4 235/434] media: vivid: media_device_cleanup was called too early
Date
From: Hans Verkuil <hverkuil-cisco@xs4all.nl>

[ Upstream commit 8ffd573c25e5fac1daeeffc592e2ed6bc6a3d947 ]

Running the contrib/test/test-media script in v4l-utils with the vivid argument
will cause this kernel warning:

[ 104.748720] videodev: v4l2_release
[ 104.748731] ------------[ cut here ]------------
[ 104.748750] DEBUG_LOCKS_WARN_ON(lock->magic != lock)
[ 104.748790] WARNING: CPU: 6 PID: 1823 at kernel/locking/mutex.c:938 __mutex_lock+0x919/0xc10
[ 104.748800] Modules linked in: rc_cec vivid v4l2_tpg videobuf2_dma_contig cec rc_core v4l2_dv_timings videobuf2_vmalloc videobuf2_memops
videobuf2_v4l2 videobuf2_common videodev mc vmw_balloon vmw_vmci button vmwgfx
[ 104.748845] CPU: 6 PID: 1823 Comm: sleep Not tainted 5.4.0-rc1-test-no #150
[ 104.748853] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/29/2019
[ 104.748867] RIP: 0010:__mutex_lock+0x919/0xc10
[ 104.748878] Code: 59 83 e8 9a fc 16 ff 44 8b 05 23 61 38 01 45 85 c0 0f 85 ef f7 ff ff 48 c7 c6 a0 1f 87 82 48 c7 c7 a0 1e 87 82 e8 cd bb
f7 fe <0f> 0b e9 d5 f7 ff ff f6 c3 04 0f 84 3b fd ff ff 49 89 df 41 83 e7
[ 104.748886] RSP: 0018:ffff88811a357b80 EFLAGS: 00010286
[ 104.748895] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[ 104.748902] RDX: 0000000000000003 RSI: 0000000000000004 RDI: ffffed102346af62
[ 104.748910] RBP: ffff88811a357cf0 R08: ffffffff81217c91 R09: fffffbfff061c271
[ 104.748917] R10: fffffbfff061c270 R11: ffffffff830e1383 R12: ffff8881a46103c0
[ 104.748924] R13: 0000000000000000 R14: ffff8881a4614f90 R15: ffff8881a46153d0
[ 104.748933] FS: 0000000000000000(0000) GS:ffff8881b6780000(0000) knlGS:0000000000000000
[ 104.748940] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 104.748949] CR2: 00007f163fc9ca20 CR3: 0000000003013004 CR4: 00000000001606e0
[ 104.749036] Call Trace:
[ 104.749051] ? _raw_spin_unlock+0x1f/0x30
[ 104.749067] ? llist_add_batch+0x33/0x50
[ 104.749081] ? tick_nohz_tick_stopped+0x19/0x30
[ 104.749130] ? v4l2_release.cold+0x6c/0xd6 [videodev]
[ 104.749143] ? mutex_lock_io_nested+0xb80/0xb80
[ 104.749153] ? vprintk_emit+0xf2/0x220
[ 104.749191] ? vivid_req_validate+0x40/0x40 [vivid]
[ 104.749201] ? printk+0xad/0xde
[ 104.749211] ? kmsg_dump_rewind_nolock+0x54/0x54
[ 104.749226] ? locks_remove_file+0x78/0x2b0
[ 104.749248] ? __fsnotify_update_child_dentry_flags.part.0+0x170/0x170
[ 104.749281] ? vivid_req_validate+0x40/0x40 [vivid]
[ 104.749321] ? v4l2_release.cold+0x6c/0xd6 [videodev]
[ 104.749361] v4l2_release.cold+0x6c/0xd6 [videodev]
[ 104.749378] __fput+0x15a/0x390
[ 104.749393] task_work_run+0xb2/0xe0
[ 104.749407] do_exit+0x4d0/0x1200
[ 104.749422] ? do_user_addr_fault+0x367/0x610
[ 104.749431] ? release_task+0x990/0x990
[ 104.749449] ? rwsem_spin_on_owner+0x170/0x170
[ 104.749463] ? vmacache_find+0xb2/0x100
[ 104.749476] do_group_exit+0x85/0x130
[ 104.749487] __x64_sys_exit_group+0x23/0x30
[ 104.749500] do_syscall_64+0x5e/0x1c0
[ 104.749511] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 104.749520] RIP: 0033:0x7f163fc5c9d6
[ 104.749536] Code: Bad RIP value.
[ 104.749543] RSP: 002b:00007ffe6f3bec58 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
[ 104.749553] RAX: ffffffffffffffda RBX: 00007f163fd4d760 RCX: 00007f163fc5c9d6
[ 104.749560] RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
[ 104.749567] RBP: 0000000000000000 R08: 00000000000000e7 R09: ffffffffffffff80
[ 104.749574] R10: 00007ffe6f3beb24 R11: 0000000000000246 R12: 00007f163fd4d760
[ 104.749581] R13: 0000000000000002 R14: 00007f163fd56428 R15: 0000000000000000
[ 104.749597] ---[ end trace 66f20f73fc0daf79 ]---

This is caused by media_device_cleanup() which destroys
v4l2_dev->mdev->req_queue_mutex. But v4l2_release() tries to lock
that mutex after media_device_cleanup() is called.

By moving media_device_cleanup() to the v4l2_device's release function it is
guaranteed that the mutex is valid whenever v4l2_release is called.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/media/platform/vivid/vivid-core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/vivid/vivid-core.c b/drivers/media/platform/vivid/vivid-core.c
index 53315c8dd2bb..f6a5cdbd74e7 100644
--- a/drivers/media/platform/vivid/vivid-core.c
+++ b/drivers/media/platform/vivid/vivid-core.c
@@ -616,6 +616,9 @@ static void vivid_dev_release(struct v4l2_device *v4l2_dev)

vivid_free_controls(dev);
v4l2_device_unregister(&dev->v4l2_dev);
+#ifdef CONFIG_MEDIA_CONTROLLER
+ media_device_cleanup(&dev->mdev);
+#endif
vfree(dev->scaled_line);
vfree(dev->blended_line);
vfree(dev->edid);
@@ -1580,7 +1583,6 @@ static int vivid_remove(struct platform_device *pdev)

#ifdef CONFIG_MEDIA_CONTROLLER
media_device_unregister(&dev->mdev);
- media_device_cleanup(&dev->mdev);
#endif

if (dev->has_vid_cap) {
--
2.20.1


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